This invention relates to the dehydrogenation of paraffins over a catalyst having a superior selectivity for dehydrogenation. More particularly, it relates to novel, sulfided composites of Group VIII metals, tin, and large-pore zeolites and their use in catalyzed paraffin dehydrogenation.
Composites of Group VIII noble metals are multifunctional in that they have substantial and concurrent activity for isomerization, cracking and dehydrogenation reactions. The isomerization and cracking activities can be inhibited by using several expedients. These expedients, however, suffer from limited catalyst life and problems with separating the dehydrogenated product from unwanted by-products. For instance, in the dehydrogenation of isobutane to form isobutene, substantial quantities of n-butane are produced, which are difficult to separate from the isobutene.